學號(請不用加任何符號)

4 + 7

(a)  

18 - 9

(a)  

13 - 7

(a)  

6 + 8

(a)  

5 + 4

(a)  

8 + 7

(a)  

3 + 7

(a)  

8 - 5

(a)  

11 - 6

(a)  

4 + 8

(a)  

9 + 5

(a)  

6 + 4

(a)  

10 - 5

(a)  

15 - 6

(a)  

11 - 9

(a)  

13 - 5

(a)  

(a)   + 5 = 12

1 + (a)   = 10

16 - (a)   = 8

(a)   - 2 = 8